The prefrontal cortex (PFC) is located in the very front of the brain, just behind the forehead. In charge of abstract thinking and thought analysis, it is also responsible for regulating behavior. This includes mediating conflicting thoughts, making choices between right and wrong, and predicting the probable outcomes of actions or events. This brain area also governs social control, such as suppressing emotional or sexual urges. Since the prefrontal cortex is the brain center responsible for taking in data through the body's senses and deciding on actions, it is most strongly implicated in human qualities like consciousness, general intelligence, and personality.
This vital region of the brain regulates thought in terms of both short-term and long-term decision making. It allows humans to plan ahead and create strategies, and also to adjust actions or reactions in changing situations. Additionally, the PFC helps to focus thoughts, which enables people to pay attention, learn, and concentrate on goals. This area is also the part of the brain that allows humans to consider several different yet related lines of thinking when learning or evaluating complex concepts or tasks. The prefrontal cortex also houses active, working memory.
Since the PFC controls intense emotions and impulses, it is sometimes referred to as the seat of good judgment. As such, a properly functioning prefrontal cortex inhibits inappropriate behaviors — including delaying gratification of needs, for things like food or sex — while encouraging wise, acceptable choices. In part, this occurs because it works to allow humans to balance immediate reward with long-term goals.
The prefrontal cortex has remarkably expanded in size throughout human evolution, culminating in modern Homo sapiens. This suggests a strong selection pressure in favor of its continued growth and development. The size of the PFC relative to the rest of the brain has also increased over that time; while the brain itself has only increased in size about threefold in the past five million years, the size of the PFC has increased sixfold.
Medical studies have shown that the PFC is the last section of the brain to mature. In other words, while all other brain regions are fully developed early in life, its development is not complete until around age 25. Magnetic resonance imaging (MRI) research has revealed that the prefrontal cortex changes a great deal during adolescence, as the brain's myelin matures and connects all regions of the brain together. This late growth and development is likely the reason that some otherwise intelligent and sensible teens engage in high-risk or excessive behaviors even though they understand the potential dangers.
Damage to the PFC
Unfortunately, the PFC is one of the brain regions most susceptible to injury. When the pathways between the prefrontal cortex and the rest of the brain are damaged or altered, serious personality changes can result. This is logical, since the PFC regulates so many behavior and thought-processing pathways, but can be debilitating and difficult for the injured individual as well as his family and social circle. A person who had been reserved and contemplative can become reckless and impulsive after such an injury. Likewise, a formerly outgoing person can become quiet and withdrawn.
A damaged PFC can negatively impact a person's ability to assess situations or perform tasks, particularly those of a moral or ethical nature. Since social judgements are made in this brain area, these people can also be rendered unable to discern appropriate behavior or suffer from emotional distress, such as irrational fears, anxiety, euphoria, and irritability. Some studies have found weak interconnections between the PFC and the rest of the brain among criminals, sociopaths, drug addicts, and schizophrenics, which may be further evidence of the importance of this part of the brain in individual behavior and decision-making.